grub screw=set screw (though I like "the coupling of maggots" definition, but that don't happen in Nature, grubs are a sexually immature insect form)
ALAN frames were "glued and screwed" (more sex, huh?) as the tubes and lugs were/are threaded, but AFAIK the Vitus frames were strictly bonded: glue but no screwing...now everybody git yer heads out of the gutter!